fix header

app.py

@@ -100,7 +100,7 @@ class BZHStableSignatureDemo(object):
         api_key = os.getenv('BZH_API_KEY')
         print("api_key = ", api_key)
         if api_key:
-            headers['BZH_API_KEY'] = api_key
+            headers['x-bzh-api-key'] = api_key
         print("headers = ", headers)
         response = requests.post('https://bzh.imatag.com/bzh/api/v1.0/detect',
                                  json=data, headers=headers)